About 10 years back I tested the water by offering a significant collection of singles via eBay. (80+ Sarah records)
Top bid was over £800 on the proviso that I took them up to London ... the prospective buyer (who was a ****) transferred me £50 in advance.
On arrival he cherry picked a couple...
Discogs seems to be the established market place.
It's knocked the arse out of a lot of the 'big score' to an extent by establishing the market place with so much volume traded.
Classic 70s albums in good nick. .... If you sell bulk you'll do well to get more than £2 a disc.
If you DYR and spend...
Don't use eBay.
The buyers have no concept of 'fair condition'.
I'll occasionally buy from eBay and if someone describes an L.P. as fair I expect a somewhat bashed up sleeve and a disc with a few crackles ..
Lovely.
The buyers expect mint.
....and boy oh boy, do they complain.